1. Field of the Invention
The invention relates in general to a power supply, and more particularly to a multi-channel power supply and a current balancing control method thereof.
2. Description of the Related Art
The normal operation of an electronic device relies on power supply. No matter an electronic device is as big as a medical apparatus or communication network system or as small as a computer central processing unit (CPU), the electronic device all needs a stable power supply. However, conventional single power supply is unable to satisfy such a need. Along with the advance and progressing in the semiconductor technology, the working voltage of a computer central processing unit is getting lower and lower, and the operating speed is getting faster and faster. To support high efficiency operation, the computer central processing unit needs a larger volume of current. Due to the restriction in the dynamic characteristics of external elements (such as slew rate), conventional uni-channel power supply is unable to provide a sufficient volume of current to the computer central processing unit within a unit time. Therefore, multi-channel power supply starts to be used for providing power to the computer central processing unit, not only providing a more stable current output, but also outputting a smaller ripple voltage.
The multi-channel power supply, also referred as interleaved-phase switch power supply, equivalently uses multiple uni-channel power supplies to provide power to the loading in a parallel manner. The largest challenge for the parallel interleaved-phase is to assure that the loading current is uniformly distributed to each power supply. To assure that the loading current is uniformly distributed to each power supply, the conventional multi-channel power supply must use a comparator. By doing so, the conventional multi-channel power supply is likely affected by the bias voltage of the comparator and is also subjected to the restriction in the bandwidth of the comparator.